Cleaning the carbs is pretty straight forward, the main thing is to be careful when cleaning the jets as they are brass. A good carb cleaner and use the manual to get settings for float height and mixture screw.

is been sat for about 2 years (bought a house!!). but before that it seem to run fine.

it sounds like it's missing a cylinder and is really lumpy. Almost sounds like a twin. The plugs appear to be sparking though, so I think I can rule out the plugs and i've tried a different set of coil packs.

After 2 years the carbs will need a good clean as the petrol will be rank, it's also possible that the float plungers will be stuck, which is prob why it's missing. Change the fuel in the tank as well. New filter and clean out the fuel pump.

U could try redex.empty ur tank,then a wee bit Fresh petrol and loads redex.probably won't Work but it's easy and quick.Balancing the carbs is quite easy if u can reach them,but it's likelyIt's just bunged up carbs and off petrol.Busters do a vaccum guage. 40/50 quid

cool thanks guys! I going to attempt to take off the carbs this evening.

Do you think, I'll need to replace the rubber gaskets and seals when I'm cleaning the carbs ? I read through the Haynes manual and as always, it's say replace this that and the other, but does it normally need it?

What if there is a fuel supply problem due to clogged fuel filter or fuel line?

All of the above is sound advice but I'd be tempted to keep it simple at first.

As aslready said, drain tank and shove some new fuel in there, then check the fuel filter (it's easy to remove when tank is drained etc) and check the fuel supply line out of the tank to the filter, then the line from the filter to the pump, and then the line from the pumo going over to the carbs. You;re looking for blockages AND kinks or perished rubber.

If that all checks out (it' only take about 30 mins and is dead easy) then I'd then sigh and start dissassembling the carb body, after I had a fag and mug of tea

I could the plunge in the end and took off the carbs and cleaned them myself. (Actually not as diffucult as I first thought). Although it took some time to take them off the bike and put back in!!

One of the jets was completely blocked! so after a good clean in carb cleaner and some pressurised air I stuck the carbs back on and it now start straight off the button, with just a little choke and runs sweet as a nut now.

Fuel pump is under the tank, just in front of the rear shock, but from recollection, it's not really disassembly-able (good english there). The fuel filter is an in-line one that bolts to the underside of the tank and is worth replacing whilst you are in the mood.

Also before jumping to the carbs as the problem, check the battery is properly charged, if the battery is low you'll get a week spark and it will be sluggish., but it does sound like they l could do with a clean.